Method and system for addressing audio-visual content fragments

ABSTRACT

A process is disclosed for applying an audio-visual addressing scheme to locate fragments of audio-visual content. The process comprises a definition sub-process, an encoding sub-process, and a decoding sub-process. The definition sub-process defines a logical model for a class of audio-visual media. The logical model is used in the encoding sub-process for encoding an address for an audio-visual resource fragment belonging to the class of audio-visual media. The logical model is also used for locating the audio-visual resource fragment that is associated with the address.

COPYRIGHT NOTICE

This patent specification contains material that is subject to copyrightprotection. The copyright owner has no objection to the reproduction ofthis patent specification or related materials from associated patentoffice files for the purposes of review, but otherwise reserves allcopyright whatsoever.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to retrieval of data from databases, and in particular, to retrieval of audio-visual data.

BACKGROUND ART

The advent of technology providing mass-market access to the Internetplaces vast amounts of on-line information within relatively easy reach.The World Wide Web (WWW) (hereunder, the Web) underpins much of thegrowth of Internet use, particularly because of the ease of use, andalso due to the intuitive user interface presented by Web browsersUniversal Resource Indicators (URIs) are a ubiquitous addressing featureused to locate target resources in the Web context. This is particularlyrelevant when Web pages are used in conjunction with a Common GatewayInterface (CGI) scripting application, which allows the Web page tobecome, in essence, the front end of a myriad of databases accessibleover the Internet.

Notwithstanding the explosive progress described however, a Web user is,in most cases, unable to “drill down” beyond a certain level of data,and must, in many cases, down-load an inconveniently large andcumbersome amount of information in order to locate useful information.Illustrating this fact, consider investigating all flights from Londonto Moscow departing from Heathrow airport on a given date. In order tomake a selection based on a number of criteria such as departure time,airline, number of stops and so on, a long list of flights typicallyneeds to be down-loaded and scanned, either manually or using a back-endapplication on a local personal computer (PC).

Further exemplifying the problem, certain types of data such as, forexample, audio-visual (AV) data, typically manifest themselves asmonolithic blocks of information. The internal structure of such data,whether it be a particular video segment, or fragment, in a movie, or aspecific movement in a symphony, is neither visible, nor addressible, orconsequently accessible in terms of fragments.

Taking a more extreme example, off-line audio-visual data, in the formof celluloid film archives, paper-based libraries, and a wealth of othersources, are also not addressable, and are thus invisible andinaccessible at the “fragment” level. Although particular books can belocated, by call number and location in a library, specific chaptersthereof are not visible or addressable, and consequently, notaccessible.

Extensible Markup Language (XML) provides a drill down capability for alimited sub-set of on-line information, namely information which iscoded in XML However, useful as this may be, the overwhelming bulk ofavailable information has been produced in other programming formatssuch as Hypertext Markup Language (HTML), or alternatively, is in hardcopy form in physical archives and libraries. The aforementioned typesof information are referred to as “legacy” information.

It is an object of the present invention to substantially overcome, orat least ameliorate, one or more disadvantages of existing arrangements.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to substantially overcome, orat least ameliorate, one or more disadvantages of existing arrangements.

According to a first aspect of the invention, there is provided a methodfor addressing an AV fragment of an AV resource over a network, to anarbitrary level of resolution, said AV resource being a member of aclass of AV resources, wherein a logical model is associated withmembers of the class of AV resources; said method comprising steps of:

determining a URI network address for the AV resource;

applying the logical model to the AV resource to form a hierarchicalrepresentation of the AV resource including a representation of the AVfragment;

determining a fragment identifier for the fragment dependent upon therepresentation of the AV fragment; and

combining the URI network address and the fragment identifier to form aURI reference, being an address for the AV fragment.

According to a further aspect of the invention, there is provided amethod for locating an AV fragment of an AV resource over a network, toan arbitrary level of resolution, said AV resource being a member of aclass of AV resources, wherein a logical model is associated withmembers of the class of AV resources; said method comprising steps of:

using a URI network address portion of a URI reference to locate the AVresource;

identifying (i) a type of the AV resource, and (ii) the logical model,dependent upon one of (a) the fragment identifier, (b) the URI, and (c)the fragment identifier and the URI; and

applying an XPath based addressing scheme to the fragment identifier,said scheme including at least one of a time axis, a time function, aregion axis, and a region function, for addressing temporal and spatialfragments of the AV resource, thereby locating the AV fragment.

According to a further aspect of the invention, there is provided amethod for addressing an AV fragment of an AV resource over a network,to an arbitrary level of resolution, said AV resource being a member ofa class of AV resources, wherein a logical model is associated withmembers of the class of AV resources; said method comprising steps of:

determining a URI network address for the AV resource;

applying the logical model to the AV resource to form a hierarchicalrepresentation of the AV resource including a representation of the AVfragment;

determining a fragment identifier for the fragment dependent upon therepresentation of the AV fragment, including a sub-step of identifying(i) a type of the AV resource, and (ii) the logical model, dependentupon one of (a) the fragment identifier, (b) the URI, and (iii) thefragment identifier and the URI; wherein said identifying step comprisesa sub-step of applying an XPath based addressing scheme to the fragmentidentifier, said scheme including at least one of a time axis, a timefunction, a region axis, and a region function, for addressing temporaland spatial fragments of the AV resource; and

combining the URI network address and the fragment identifier to form aURI reference, being an address for the AV fragment.

According to a further aspect of the invention, there is provided anapparatus for addressing an AV fragment of an AV resource over anetwork, to an arbitrary level of resolution, said AV resource being amember of a class of AV resources, wherein a logical model is associatedwith members of the class of AV resources; said apparatus comprising:

first determining means for determining a URI network address for the AVresource;

applying means for applying the logical model to the AV resource to forma hierarchical representation of the AV resource including arepresentation of the AV fragment;

second determining means for determining a fragment identifier for theAV fragment dependent upon the representation of the AV fragment; and

combining means for combining the URI network address and the fragmentidentifier to form a URI reference, being an address for the AVfragment.

According to a further aspect of the invention, there is provided anapparatus for addressing an AV fragment of an AV resource over anetwork, to an arbitrary level of resolution, said AV resource being amember of a class of AV resources, wherein a logical model is associatedwith members of the class of AV resources; said apparatus comprising:

first determining means for determining a URI network address for the AVresource;

first applying means for applying the logical model to the AV resourceto form a hierarchical representation of the AV resource including arepresentation of the AV fragment;

second determining means for determining a fragment identifier for thefragment dependent upon the representation of the AV fragment, includingidentifying means for identifying (i) a type of the AV resource, and(ii) the logical model, dependent upon one of (a) the fragmentidentifier, (b) the URI, and (iii) the fragment identifier and the URI;wherein said identifying means comprises second applying means forapplying an XPath based addressing scheme to the fragment identifier,said scheme including at least one of a time axis, a time function, aregion axis, and a region function, for addressing temporal and spatialfragments of the AV resource; and

combining means for combining the URI network address and the fragmentidentifier to form a URI reference, being an address for the AVfragment.

According to a further aspect of the invention, there is provided anapparatus for locating an AV fragment of an AV resource over a network,to an arbitrary level of resolution, said AV resource being a member ofa class of AV resources, wherein a logical model is associated withmembers of the class of AV resources, said apparatus comprising

utilisation means for using a URI network address portion of a URIreference to locate the AV resource;

identifying means for identifying (i) a type of the AV resource, and(ii) the logical model, dependent upon one of (a) the fragmentidentifier, (b) the URI, and (c) the fragment identifier and the URI;and

applying means for applying an XPath based addressing scheme to thefragment identifier, said scheme including at least one of a time axis,a time function, a region axis, and a region function, for addressingtemporal and spatial fragments of the AV resource, thereby locating theAV fragment.

According to a further aspect of the invention, there is provided acomputer readable memory medium for storing a program for apparatus foraddressing an AV fragment of an AV resource over a network to anarbitrary level of resolution, said AV resource being a member of aclass of AV resources, wherein a logical model is associated withmembers of the class of AV resources; said program comprising:

code for a first determining step for determining a URI network addressfor the AV resource;

code for an applying step for applying the logical model to the AVresource to form a hierarchical representation of the AV resourceincluding a representation of the AV fragment;

code for a second determining step for determining a fragment identifierfor the AV fragment dependent upon the representation of the AVfragment; and

code for a combining step for combining the URI network address and thefragment identifier to form a URI reference.

According to a further aspect of the invention, there is provided acomputer readable memory medium for storing a program for apparatus foraddressing an AV fragment of an AV resource over a network, to anarbitrary level of resolution, said AV resource being a member of aclass of AV resources, wherein a logical model is associated withmembers of the class of AV resources; said program comprising:

code for a first determining step for determining a URI network addressfor the AV resource;

code for a first applying step for applying the logical model to the AVresource to form a hierarchical representation of the AV resourceincluding a representation of the AV fragment;

code for a second determining step for determining a fragment identifierfor the fragment dependent upon the representation of the AV fragment,including code for an identifying step for identifying (i) a type of theAV resource, and (ii) the logical model, dependent upon one of (a) thefragment identifier, (b) the URI, and (iii) the fragment identifier andthe URI; wherein said code for the identifying step comprises code for asecond applying step for applying an XPath based addressing scheme tothe fragment identifier, said scheme including at least one of atime-axis, a time function, a region axis, and a region function, foraddressing temporal and spatial fragments of the AV resource; and

code for a combining step for combining the URI network address and thefragment identifier to form a URI reference, being an address for the AVfragment.

According to a further aspect of the invention, there is provided acomputer readable memory medium for storing a program for apparatus forlocating an AV fragment of an AV resource over a network, to anarbitrary level of resolution, said AV resource being a member of aclass of AV resources, wherein a logical model is associated withmembers of the class of AV resources; said program comprising:

code for a utilisation step for using a URI network address portion of aURI reference to locate the AV resource;

code for an identifying step for identifying (i) a type of the AVresource, and (ii) the logical model, dependent upon one of (a) thefragment identifier, (b) the URI, and (c) the fragment identifier andthe URI; and

code for an applying step for applying an XPath based addressing schemeto the fragment identifier, said scheme including at least one of a timeaxis, a time function, a region axis, and a region function, foraddressing temporal and spatial fragments of the AV resource, therebylocating the AV fragment.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the prior art, and a preferred embodiment of thepresent invention will now be described with reference to the drawings,in which:

FIG. 1 depicts a prior art system for accessing audio data on a CD ROMusing the Internet;

FIG. 2 illustrates indexing typically provided for a CD ROM according toFIG. 1;

FIG. 3 depicts a preferred embodiment of the addressing method inrelation to CD ROMs according to the present invention;

FIG. 4 shows a process for applying an audio-visual addressing scheme tolocate fragments of audio-visual content;

FIG. 5 illustrates application of the method in FIG. 3 to addressing afragment of audio data on a CD ROM;

FIG. 6 depicts the preferred embodiment applied to addressing a fragmentof digital video content on a CD ROM;

FIG. 7 shows a process for locating audio-visual fragments using the“avptr” addressing scheme;

FIG. 8 shows a process for evaluating a location step in FIG. 7;

FIG. 9 shows an exemplary process for locating video data on a digitalvideo tape;

FIG. 10 shows an exemplary process for locating visual data in a region;

FIG. 11 shows an exemplary process for locating audio data on an audioCD;

FIG. 12 depicts the locating of resources using conventional URIs;

FIG. 13 illustrates use of extended URIs for fragment location accordingto the preferred embodiment; and

FIG. 14 is a schematic block diagram of a general purpose computer uponwhich the preferred embodiment of the present invention can bepracticed.

DETAILED DESCRIPTION INCLUDING BEST MODE

Where reference is made in any one or more of the accompanying drawingsto steps and/or features, which have the same reference numerals, thosesteps and/or features have for the purposes of this description the samefunction(s) or operation(s), unless the contrary intention appears.

It is noted that the introductory part of the description makesreference, for illustrative purposes, to audio and video content whichis stored on Compact Disk Read Only Memory (CD ROM) media accessed by a“Juke Box” device which is capable of storing a number of such disks andaccessing them according to an address.

FIG. 1 depicts a prior art system used to locate an audio content CD ROM312 using the Internet 308 as a vehicle. A user (not shown) uses apersonal computer (PC) 304 which is connected to the Internet 308 inorder to connect to the server 306 of an on-line music provider. Theserver 306 is connected to a CD ROM juke box 310 which houses aplurality of CD ROMs 312, 316. Each CD ROM 312, 316 contains individualsongs exemplified, for illustrative purposes only, by bold lines 314,318 respectively. The user has a paper description 300 of the desired CDROM 312 containing a title 326 of the CD ROM, and also a list of thesongs 302, 320. The user uses a Universal Resource Indicator (URI) 324which “points” to the address of the CD ROM 312, and the user is able todownload music from the CD ROM 312 over the system.

In FIG. 2, the CD ROM 312 can be portrayed in a description 400 ascontaining a list of songs 402, 404 under a title 414, where the song404 has indices 410 and 412 which point to particular segments withinthe song 404. Terminology such as “songs” is used for illustration inthis part of the description, noting that in fact, as described, theaudio content is actually stored on CD ROM as noted. For example inclassical music where the “song” 402 can be an individual movement of asymphony, and therefore can be quite long, the index 1 (ie 410) canpoint to a trumpet solo, and the index r (ie 412) can point to a violinsolo of interest. Depending upon the capabilities of the server 306 andjuke box 310 in FIG. 1, the user can address the desired CD ROM 312, andaddress a desired index 410. It is noted however, with reference to bothFIG. 1, and to FIG. 2, that the user is limited to addressing, and soaccessing, material only down to the level of the articular CD (ie 312),or perhaps the specified predefined index (ie 410). It is not possibleto “drill down” to an arbitrary further specified level of fine graindetail.

FIG. 3 depicts an illustrative embodiment of an addressing method, inthis case to be used in relation to audio, CD ROMs. The CD ROM 312,formerly described by the description 400 which contains a list ofindividual songs 402, each of which may contain a level of indexing (eg410 see FIG. 2) is extended, using a logical model based uponconsecutive time blocks or slices, and using a set of rules defining howthe logical model is to be applied, into a hierarchical representationcomprising both the description 400 and the further description 500comprising time blocks 502 to 512. The logical model, when applied tothe CD ROM 312, serves to form a hierarchical representation of theotherwise monolithic AV content of the CD ROM 312. The model therebyenables systematic and rapid addressing of arbitrary content fragmentson a time block basis, and provides the desired arbitrary drill downcapability. Using the described representation, a user is able, forexample, to select an arbitrary fragment of audio content on the CD ROM312 by specifying a fragment address, or fragment identifier, of theform “title/song1/block 2-block j-3”, where j is an arbitrary index asshown in FIG. 3. The present logical model is used for illustrativepurposes, and more advantageous logical models and addressing schemesare proposed later in the description. In FIG. 3 song 402 is shown tocomprise blocks 502 to 506, song 2 comprising blocks from the blockafter 504 through to block 506 and so on.

FIG. 4 shows a process 900 for applying an audio-visual (ie AV)addressing scheme to locate fragments of audio-visual content. Theprocess 900 comprises three sub-processes, namely a definitionsub-process 902, an encoding sub-process 904, and a decoding sub-process906. The definition sub-process 902 defines, as depicted by an arrow910, a logical model 908 for a class of AV media. After the definitionsub-process 902, the logical model 908 is used (as depicted by an arrow912) in the encoding sub-process 904 for encoding an address for anaudio-visual resource fragment belonging to the class of AV media. Thelogical model 908 is also used (as depicted by an arrow 914) forlocating the audio-visual resource fragment that is associated with theaddress.

Turning to FIG. 5, the hierarchical representation 602, comprisingdescriptions 400 and 500, is shown in a system content in more detail.By using the fragment identifier 610, derived from the hierarchicalrepresentation 602, in conjunction with the URI 324 (see FIG. 1), anextended URI 606 (commonly referred to as a “URI reference” is shown toincorporate both the URI 324 described in relation to FIG. 1, and anadditional fragment identifier 608. The URI reference can thus be usedas an address to the CD 312, and further, to the desired fragment 314.

FIG. 6 depicts another hierarchical representation 706, determined usinga logical model appropriate for digital video. In this example, asequence of digital video shots 700 is recorded on a CD ROM 724. Thelogical model selected resolves the video sequence 700 into frames eg708, each frame being further resolved into x intervals eg 710 and yintervals eg 722. This logical model is used for illustrative purposes,and more advantageous logical models are proposed later in thedescription. Using the described representation, a user is able, forexample, to select an arbitrary spatial fragment of video content on aspecified frame of the CD ROM 724 by specifying a fragment address, orfragment identifier, of the form “Title/frame1/x1-x2; y1-y2”. The xinterval from x1 (726) to x2 (728) and the y interval from y1 (730) toy2 (732) address the spatial region 704 within the frame 702 in the setof digital video shots 700. The URI reference 716 therefore contains aportion 734 prior to the hash sign 720 which addresses the digital videodisc 724, while the portion 736 after the hash sign 720 addresses thefragment 704.

Having provided an illustrative description of an embodiment of theinvention, a more detailed description is now provided. ML is utilisedas a basis for describing a preferred embodiment of the presentinvention. This is both from the standpoint of conceptual and notationalconvenience, and also because XML has significant support as arecommendation in the context of the World Wide Web Consortium (W³C).

It is shown, in the preferred embodiment, how the XML Path Language(XPath), can be extended and used in an unexpected manner in order tolocate fragments of non XML-based audio-visual content.

The XML Linking Language (Xlink) uses URI's for locating objects. Inprinciple, modified URIs can be used for locating any resource that hasidentity, for instance, an electronic document, an image, a service, acollection of other resources, a person, an corporation, or a bound bookin a library. Each resource corresponds to an entity or set of entitiesin a conceptual model. URI's can therefore be used for locating orreferencing resources other than XML documents. However, the XPath andXML Pointer Language (Xpointer) schemes that XLink currently uses foraddressing the internal structure of data objects can only be used tolocate fragments of XML documents.

As an introduction, the use of XLink, XPointer, and XPath, areconsidered in the limited context of XML documents. XPath models an XMLdocument as a tree of nodes. There are seven types of nodes, namely rootnodes, element nodes, text nodes, attribute nodes, namespace nodes,processing instruction nodes and comment nodes. XPath uses a compact,non-XML syntax to facilitate the use of XPath within URI's. An XPathlocation path consists of a ‘/’-separated list of location steps. Eachlocation step has the form:

axis :: node-test [predicates]

where axis specifies the tree relationship between the nodes selected bythe location step and the context node; node-test specifies the nodetype or the name; and predicates refine the set of nodes selected by thelocation step.

A number of syntactic abbreviations allow common cases to be expressedconcisely as follows.

@ is short for attribute::, e.g. attribute::type can be abbreviated as@type,

// is short for /descendant-or-self::node( )/,

-   -   . is short for self::node( ), and    -   .. is short for parent::node( ).

An axis specifies the tree relationship between the nodes selected bythe location step and the context node. XPath axes include child,parent, descendant, ancestor, following-sibling, preceding-sibling,following, preceding, attribute, namespace, self, descendant-or-self andancestor-or-self. The default is the child axis. XPointer extends XPathadding the string and range axes.

A node test specifies the node type or the name (such as the name of anelement or an attribute) of the nodes selected by the location step.

There can be zero or more predicates for refining the set of nodesselected by the location step. Predicates are evaluated for eachcandidate location along the specified axis, and typically test theelement type, attributes, positions, and/or other properties of thecandidate nodes.

A function library provides a set of predicate functions such as count(), position( ), id( ), last( ), etc. Each function takes zero or morearguments and returns a single result. Like XPointer, a new scheme candefine new functions to extend the core functions of XPath.

Each location step is evaluated with respect to a context. The contextis initially the document root, or more generally the results of a priorlocation step. The node set selected by the location step is the nodeset that results from generating an initial node set from the axis andnode test, and then filtering that node-set by each of the predicates inturn.

Some examples of XPath location paths are as follows:

/doc/chapter[2]/section[3]

selects the third section of the second chapter of doc

chapter[contains(string(title), “Overview”]

selects the chapter children of the context node that have one or moretitle children containing the text “Overview”

child::*[self::appendix or self::index]

selects the appendix and index children of the context node

child::*[self::chapter or self::appendix] [position( )=first( )]

selects the first chapter and appendix children of the context node

para[@type=“warning”]

selects all para children of the context node that have a type attributewith value “warning”

para[@id]

selects all the para children of the context node that have an idattribute.

XPath operates on the logical structure of an XML document, this logicalstructure being defined either explicitly by a Document Type Definition(DTD), or implicitly by arrangement of tags. For instance, the examplesgiven in the previous section assumed an XML document with thestructure, in Extended Backus-Naur Form (ENBF) as follows:

doc ::= toc chapter+ appendix* index

chapter ::= section+

section ::= para+

appendix ::= section+

where “toc” means “table of contents”, “+” means “one or more, “*” meanszero or more”, and the composite description presented above describes,in expanded form, a document comprising a table of contents, one or morechapters, zero or more appendices, and an index, where each chaptercomprises one or more sections, where each section comprises one or moreparagraphs, and finally where each appendix comprises one or moresections.

In an XML document, each of these structures is marked by a pair ofappropriately named tags. The tag markup allows the logical structure ofthe document to be determined unambiguously. Hence, any application thatunderstands the syntax of XML can determine the location of thedocument's components. Any application that understands the XPath andXPointer notations can use an URI with an XPath/XPointer fragmentidentifier to locate parts of the document.

Audio-visual, or AV content, is not stored as XML documents and cannotbe marked up. However, given an unambiguous logical structure, or model,a modified XPath location/addressing method can be used. Hence, for eachclass of AV content, in the first instance, an unambiguous logicalstructure must be defined, and in order to make it widely accessible,the logical structure should preferably be published. By an unambiguouslogical structure or model, it is meant that different persons andapplications will segment given content in exactly the same way giventhe model.

Considering one type of AV content, for instance, Digital Video formatas used by digital video cameras, this can be modelled as:

dv ::= frame*

where this means a digital video comprising one or more frames.

In the case, for example, where compatible digital video camerasgenerate meta-data to represent and record the instances the camerastarts recording (designated a REC event), a shot can be defined as aninterval between two REC event. In this case, the model for DV formatis:

dv ::= shot*

shot ::= frame+

meaning a digital video comprising zero or more shots, each shotcomprising one or more frames.

As another example, the logical structure of Compact Disc Audio can bemodelled as follows:

cdAudio ::= track*

track ::= channel channel index*

channel ::= sample*

meaning an audio CD comprising zero or more tracks, each trackcomprising two channels, and zero or more indices, and each channelcomprising zero or more samples.

Considering a more complex example, consider Digital Video Disc, or DVD,video which can provide:

over 2 hours of high-quality digital video (over 8 on a double-sided,dual-layer disc),

up to 8 tracks of digital audio, each with as many as 8 channels

up to 32 subtitle/karaoke tracks

up to 9 camera angles (different viewpoints) can be selected duringplayback

up to 32 separate subpicture channels

Other data types include Video Manager Information files, Video TitleSet files, Program Chain Information files, still picture Video Objects,attributes for Title, Part_of_Titles, and Menus, Time Map Tables,Part_of_Title Search Pointers, and Navigation Commands.

DVD-Video content is broken into titles and chapters (or parts oftitles). Titles are made up of cells linked together by one or moreprogram chains (PGC). Individual cells can be used by more than one PGC.Different PGCs define different sequences through mostly the samematerial. Additional material for camera angles and branching isinterleaved together in small chunks. The DVD player jumps from chunk tochunk, skipping over unused angles or branches, to stitch together theseamless video.

One logical model for DVD-Video is:

dvdVideo ::= mainMenu? title* subpicture* file*

mainMenu ::= menu*

menu ::= menu*

title ::= chapter+

chapter ::= view+ audio+ subtitle*

view ::= frame+

audio ::= channel+

channel ::= sample+

The previous logical models each relate to a class of AV content, namelydigital video, compact disc audio, and digital video disk. As noted, theapplication of the logical models to the associated AV content produceshierarchical representations of the AV content which supports addressingof fragments of the content.

Turning to the aspect of addressing, each location step is evaluatedwith respect to a context. The context is initially the root node,dvdVideo in this case. In general, the context is the results of a priorlocation step. The node set selected by the location step is the nodeset that results from generating an initial node set from the axis andnode test, and then filtering that node-set by each of the predicates inturn.

FIG. 7 shows a process 1000 for locating audio-visual fragments usingthe “avptr” addressing scheme. This process 1000 depicts the decodingsub-process 906 in FIG. 4. A URI reference 1002(http://www.apxcom.com/products/dvd0111#avptr(/dvdVideo/title/chapter/audio[1]))is provided, as depicted by an arrow 1004 which is equivalent to anarrow 916 in FIG. 4, to a step 1006. In the step 1006, the URI portion(http://www.apxcom.com/products/dvd011) of the URI reference 1002 isused to locate a resource. In a following step 1010, a root of thefragment address, ie dvdVideo in the URI reference 1002, is used todetermine a content type, and consequently, an associated logical model1012 (which has already been defined in the definition sub-process 902in FIG. 4). In a following step 1018, the logical model 1012 (which isequivalent to the logical model 908 in FIG. 4) is used to set theinitial context to the root node of the fragment.

Thereafter, a decision step 1022 determines whether the aforementionedsteps have determined the last location step required to locate thedesired resource fragment. If the last location step has beendetermined, the process 1000 is directed, according to a “YES” arrow1024, to a step 1026 in which the located resource fragment isprocessed. The step 1026 is a post-location processing step.

If the decision step 1022 determines that the last location step has notbeen determined, then the process 1000 is directed, according to a “NO”arrow 1028, to a step 1030 which evaluates the next location step withinthe current context. This is described in more detail with reference toFIG. 8. Thereafter, in a step 1034, node(s) are selected that satisfythe specified selection criteria (see FIG. 8 for description of thesecriteria). In a following step 1038, the context is set to the node(s)selected, and the process 1000 is then directed, according to an arrow1040, to the testing step 1022.

FIG. 8 shows a process 1100 for evaluating the “evaluation of alocation” step 1030, which is shown as a dashed box. The dashed box 1030in FIG. 8 corresponds to the sub-process 1030 in FIG. 7. The step 1030is a location step of the form axis::node-test[predicates]. In a firststep 1102 (which follows the decision step 1022 in FIG. 7 as depicted bythe arrow 1028), a hierarchical relationship specified by the axis isused to select a set of nodes within the current context. Thereafter, ina step 1106 the node test is performed, thereby selecting nodes that areof the specified node type or node name from the current node set. In afollowing step 1110, the predicates are applied to each node in thecurrent node set, selecting only those nodes that satisfy thepredicates.

The described AV location scheme can, utilising a notation and mechanismsimilar to those of XPath/XPointer, locate analog and digital AV contentwithin a database, or a plurality of databases.

A set of named functions are defined for the AV location scheme. Forinstance,

time(startTime [, endTime]) For determining whether the current contextis within the specified time. timecode(startTimecode For determiningwhether the current   [, endTimecode]) context is within the timespecified by the start and end timecodes.

The functions can be used for evaluating expressions, the evaluationalways occurring with respect to the current context.

In addition, new axes can be added, for instance, a time axis and aregion axis for locating temporal and spatial segments of the data. Theincorporation of these axes provides additional power to the concept offragment addressing, and allows drilling down to different aspects ofthe AV content.

The time axis selects, within the current context, components that occurwithin the specified start and end time. The current context is taken asstarting at time zero and progressing continuously through time innormal play time. If the end time is not specified, it is taken to bethe same as the start time and the component that occurs at or closestto the specified start time is selected.

TimeLocationStep ::= ‘time’ ‘::’ StartTime (‘,’ EndTime)?

TimeUnit ::= ‘h’ | ‘m’ | ‘s’ | ‘ms’

TimeNotation ::= ‘end’ | ([0-9]+ TimeUnit)

StartTime ::= TimeNotation

EndTime ::= TimeNotation

For example,http://www.apxcom.com/products/dvd0111#avptr(/dvdVideo/title[2]/time::0m,15m)  1]selects the first 15 minutes the second title of the specified DVD. Thisexample is designated example [1].In example [1], the method works as follows:

Selection step Meaning Context after the selection step axis (default ischild::) all the children of the all the children of the dvdVideocontext node node, that is, all the mainMenu, title, subpicture and filenodes node-test Title[2] any title node whose the 2^(nd) title nodes andposition is 2 predicate axis Time:: arrange the current unchangedselection continuously in time starting at time zero node-test 0m,15mall content inside the the first 15 minutes of the 2^(nd) time interval0 min to title 15 min

FIG. 9 depicts the example [1] as a process 1200 for locating video dataon a digital video tape, using the “avptr” addressing scheme. A URIreference 1202 (depicted as [1] in the body of the description) isprovided, as depicted by an arrow 1218, to a step 1204 in which the URIportion (ie http://www.apxcom.com/products/dvd0111) of the URI reference1202 is used to locate a resource. In a following step 1206, the root ofthe fragment address, ie dvdVideo in the URI reference 1202, is used todetermine a content type, and consequently, an associated logical model1208. In a following step 1210, the logical model 1208 is used to setthe initial context to the root node of the fragment.

Thereafter, the process 1200 is directed to a step 1212 which evaluatesthe location step, ie title[2] in the URI reference 1202, therebyselecting the 2^(nd) title node. Thereafter, in a step 1214, thelocation step ie time::0m,15m in the URI reference 1202 is evaluated,thereby selecting content within the first 15 minutes of the 2^(nd)title node. Thereafter, the process 1000 is directed to a step 1216 inwhich the located resource fragment is processed. The step 1216 is apost-location processing step.

In a variation of example [1]:http://www.apxcom.com/products/dvd0111#avptr(/dvdVideo/title[(position()=1 orposition( )=2)][time(“0m”,“15m”)]  [2]

-   -   selects the first 15 minutes of the 1^(st) and the 2^(nd) titles        of the specified DVD        As another example,        http://www.apxcom.com/products/dvd0111#avptr(/dvdVideo/title[(position(        )=1 or        position( )=2][time(“0m”,“15m”)]  [3]        selects the first 15 minutes of the first and the second titles        of the DVD.

The method, applied to example [3], works as follows:

Selection step Meaning Context after the selection step axis (default ischild::) all the children of All the children of the dvd Video thecontext node node, that is, all the mainMenu, title, subpicture and filenodes node-test title[position( ) = 1 or any title node The first andthe second title nodes and position( ) = 2] whose position is predicateeither 1 or 2 additional [time(“0m”,“15m”)] any content inside the first15 minutes of the first and predicate the time interval the secondtitles 0 min to 15 min (of each candidate node)

The timecode axis selects, within the current context, components thatoccur within the specified start and end timecode. If the end timecodeis not specified, it is taken to be the same as the start timecode andthe component that occurs at the specified start timecode is selected.The timecode is represented by a time value or a combination of date andtime values as defined in International Standards Organisation (ISO)8601. It can also be an SMPTE (ie Society of Motion Picture andTelevision Engineers) timecode in the format of HH:MM:SS:FF where FFstands for frame.

TimecodeLocationStep ::= ‘timecode’ ‘::’ StartTimecode (‘,’EndTimecode)?

TimecodeNotation ::= ‘begin’ | ‘end’ | smpteTimecode | time |(““dateTime””)

StartTimecode ::= TimecodeNotation

EndTimecode ::= TimecodeNotation

For example,http://www.apxcom.com/events/productLaunch99#avptr(/dv/shot/timecode::00:15:00:00,00:30:00:00)  [4]selects 15 minutes of clips on the specified digital video tape usingSMPTE timecodes

The region axis selects, within the current context, the 2D region thatis bounded by the specified bounding curve. The origin corresponds tothe top-left corner of a frame with the x- and y-axis coordinatesincreasing to the right and down. Coordinates are specified in(integral) pixel values. Several types of bounding curves such asrectangle and ellipse allow the (anti-clockwise) angle between its majoraxis and the x-axis to be specified. To allow a region to be specifiedfor different resolutions of the same content, the resolution of thesource from which the bounding curve is determined could be specifiedusing the range( ) function.

-   -   RegionLocationStep ::= ‘region’ ‘::’ [Range] BoundingCurve    -   BoundingCurve ::= Shape    -   Shape ::= Circle | Ellipse | Rectangle | Polygon | QuadCurve |        CubicCurve | Bspline    -   Circle ::= ‘circle(’ XCentre ‘,’ YCentre ‘,’ Radius ‘)’    -   Ellipse ::= ‘ellipse(’ XCentre ‘,’ YCentre ‘,’ Major ‘,’ Minor        ‘,’ Angle ‘)’    -   Rectangle ::= ‘rect(’ Left ‘,’ Top ‘,’ Width ‘,’ Height ‘,’        Angle ‘)’    -   Polygon ::= ‘polygon(’ Point ‘,’ Point (‘,’ Point)+ ‘)’    -   QuadCurve ::= ‘qcurve(’ Point ‘,’ Point (‘,’ Point)+ ‘)’    -   CubicCurve ::= ‘ccurve(’ Point ‘,’ Point (‘,’ Point)+ ‘)’    -   BSpline ::= ‘bspline(’ Point ‘,’ Point (‘,’ Point)+ ‘)’    -   Point ::= Integer ‘,’ Integer    -   Integer ::= [+|−] Digits    -   Angle ::= Degree    -   Range ::= ‘range(’ Integer ‘,’ Integer ‘)’

For example,http://www.apxcom.com/events/productLaunch99#avptr(/dv/shot[1]/frame[1012]/region::range(720,480)rect(40,40,60,60,45)  [5]selects a 60×60 diamond-shape region from the 1012^(th) frame of shotone of the specified digital video tape.

FIG. 10 depicts the example [5] as a process 1300 for locating visualdata in a region, using the “avptr” addressing scheme. A URI reference1302 (depicted as [5] in the body of the description) is provided, asdepicted by an arrow 1322, to a step 1304 in which the URI portion (iehttp://www.apxcom.com/events/productLaunch99) of the URI reference 1302is used to locate a resource. In a following step 1306, a root of thefragment address, ie dv in the URI reference 1302, is used to determinea content type, and consequently, an associated logical model 1308. In afollowing step 1310, the logical model 1308 is used to set the initialcontext to the root node of the fragment.

Thereafter, the process 1300 is directed to a step 1312 which evaluatesthe location step, ie shot[1] in the URI reference 1202, therebyselecting the 1^(st) shot node. Thereafter, in a step 1314, the locationstep frame[1012] in the URI reference 1302 is evaluated, therebyselecting the node of frame[1012] of the 1^(st) shot node. Thereafter ina step 1318, a location step region::range(720,480)rect(40,40,60,60,45)in the URI reference 1302 is evaluated, thereby selecting content withinthe specified rectangle of frame[1012] of the 1^(st) shot. Thereafter,the process 1300 is directed to a step 1320 in which the locatedresource fragment is processed. The step 1320 is a post-locationprocessing step.

As another example,http://www.apxcom.com/products/acd010239#avptr(/cdAudio/track[2]/channe/time::0s,60s)  [6]selects the first minute of the second tack of an audio CD which has themodel

cdAudio ::= track*

track ::= channel channel Index*

channel ::= sample*

The portion of the URI reference before the hash refers to the AVproduct, in this instance an audio CD no. 010239, belonging to a classof products, ie audio CDs, produced by the fictitious company “apxcom”,which is the resource in this instance. What follows the hash sign is an“AV” fragment identifier, or pointer for locating specific AV content onthe designated CD. The AV pointer is directed to the internal structureof the content, in this case the first minute of the second track.Therefore, the URI (Universal Resource Indicator), which is the familiarentity used in Internet addressing, when combined with a fragmentidentifier (the part of the URI reference following the hash sign), iscalled a URI reference.

The location steps work as follows:

Selection step Meaning Context after the selection step axis (default ischild::) all the children of the all the children of the cdAudio contextnode node, that is, all the track nodes node-test track[2] any tracknode the 2^(nd) track node and whose position is 2 predicate axis(default is child::) all the children of the all the children of the2^(nd) track context node node node-test channel any channel node allthe channel nodes of the 2^(nd) and track node predicate axis time::arrange the current unchanged selection continuously in time starting attime zero node-test time::0s,60s all content inside the the first minuteof the 2^(nd) track time interval 0 sec to 60 sec

FIG. 11 depicts the example [6] as a process 1400 for locating audiodata on an audio CD, using the “avptr” addressing scheme. A URIreference 1402 (depicted as [6] in the body of the description) isprovided, as depicted by an arrow 1404, to a step 1406 in which the URIportion (ie http://www.apxcom.com/products/acd010239) of the URIreference 1402 is used to locate a resource. In a following step 1408, aroot of the fragment address, ie cdAudio in the URI reference 1402, isused to determine a content type, and consequently, an associatedlogical model 1410. In a following step 1412, the logical model 1410 isused to set the initial context to the root node of the fragment.

Thereafter, the process 1400 is directed to a step 1414 which evaluatesthe location step, ie track[2] in the URI reference 1402, therebyselecting the 2^(nd) track node. Thereafter, in a step 1416, thelocation step channel in the URI reference 1402 is evaluated, therebyselecting all the channel nodes of the 2^(nd) track node. Thereafter ina step 1418, a location step time::0s,60s in the URI reference 1402 isevaluated, thereby selecting content within the 1^(st) minute of all thechannel nodes of the 2^(nd) track node. Thereafter, the process 1400 isdirected to a step 1420 in which the located resource fragment isprocessed. The step 1420 is a post-location processing step.

In a further example (no. [7]), the URI to a 15 minutes segment of thesecond movie on a DVD can have the form:http://www.apxcom.com/products/dvd0111#avptr(/dvdVideo/title[2]/time::30m,15m)  [7]while a further example (no. [8]), iehttp://www.apxcom.com/products/dvd0111#avptr(/dvdVideo/title/chapter/audio[1])  [8]will select the first audio track of the DVD.

In considering the above URI references, it is again noted that theportion of the URI before the hash sign refers to the AV product, namelythe resource. What follows the hash sign is an AV fragment identifierfor locating parts of the AV content.

FIG. 12 presents a description of a prior art scenario in the context ofan XML document 114 presented on a browser (not shown). It is noted thatthe document 114 as shown depicts a physical aspect of the XML document,whereas a user of the browser would be presented with the document in adifferent style (not shown). The document 114 describes AV content aboutthe Apollo 13 space mission. The document type is designated by areference 100, which in the present instance is a “Documentary”. Anumber of hyperlink references 104, 106 provide links to other XMLdocuments 120, 122, which describe movie sources and movie reviews (notshown) respectively. The movie sources referred to by document 120 canbe either on-line, or alternatively, can be a physical entities such asa video-cassette 128 (depicting a specific movie source in this example)produced by a company. The document 114 contains a segment 110 named“Rocket Launch” between tag delimiters 108 and 124. The rocket launchsegment commences 15 minutes after the start of the documentary asindicated by the start index 112. When a user selects the releasereference 104, the associated link depicted by an arrow 118 directs theuser to the XML document 120 describing the movie source 128 as alreadynoted. Selection of a reference 132 on the document 120 retrieves a URI126, which points, as indicated by an arrow J 30, to the physical videocassette 128. The URI 126 is seen to comprise a link to a company havinga domain name movies designated 134, where the specific cassette isdesignated “vhs0111” ie 136 in the “products” category 138. Reviewingthe aforementioned process for clarity of explanation, selection by theuser of the Apollo 13 reference 104 directs the user to the specificcassette 128 through a location process depicted by the URI 126. Notingthat the URI has a standard format and does not incorporate a fragmentidentifier, it is clear that the described scenario does not supportdrilling down to the fragment level of the non-XML AV resource. The URIdoes address the particular video cassette 128, but provides nomechanism for addressing AV data on the cassette at the fragment level.

Turning to FIG. 13, a preferred embodiment of the proposed addressingmethod is described. Selection of the preview reference 200 on the mainXML document 114 activates a link depicted by an arrow 202 which isdirected to another XML document 204. This latter document 204 describespreview AV material at the fragment level, and selection of a reference226 results in a link depicted by a dashed arrow 206 pointing to an AVfragment using an extended URI 208. The portion of the URI 208 beforethe hash relates to VHS Preview content designated “01100”, which is aproduct of a fictitious company called “movies”. The portion of the URIafter the hash is an AV pointer 212, pointing to the second video 216 ofthe vhs (214) tape, and in particular to a segment (218) starting 900seconds after the start of the documentary, and ending 1800 secondsafter the start of the documentary.

The method of addressing an arbitrary fragment of an AV resource ispreferably practiced using a conventional general-purpose computersystem 800, such as that shown in FIG. 14 wherein the processes of FIGS.4 and 7 to 11 may be implemented as software, such as an applicationprogram executing within the computer system 800. In particular, thesteps of the method of addressing an arbitrary fragment of an AVresource are effected by instructions in the software that are carriedout by the computer. The software may be divided into two separateparts; one part for carrying out the addressing methods, and anotherpart to manage the user interface between the latter and the user. Thesoftware may be stored in a computer readable medium, including thestorage devices described below, for example. The software is loadedinto the computer from the computer readable medium, and then executedby the computer. A computer readable medium having such software orcomputer program recorded on it is a computer program product. The useof the computer program product in the computer preferably effects anadvantageous apparatus for addressing an arbitrary fragment of an AVresource in accordance with the embodiments of the invention.

The computer system 800 comprises a computer module 801, input devicessuch as a keyboard 802 and mouse 803, output devices including a printer815 and a display device 814. A Modulator-Demodulator (Modem)transceiver device 816 is used by the computer module 801 forcommunicating to and from a communications network 820, for exampleconnectable via a telephone line 821 or other functional medium. Themodern 816 can be used to obtain access to the Internet, and othernetwork systems, such as a Local Area Network (LAN) or a Wide AreaNetwork (WAN).

The computer module 801 typically includes at least one processor unit805, a memory unit 806, for example formed from semiconductor randomaccess memory (RAM) and read only memory (ROM), input/output (I/O)interfaces including a video interface 807, and an I/O interface 813 forthe keyboard 802 and mouse 803 and optionally a joystick (notillustrated), and an interface 808 for the modem 816. A storage device809 is provided and typically includes a hard disk drive 810 and afloppy disk drive 811. A magnetic tape drive (not illustrated) may alsobe used. A CD-ROM drive 812 is typically provided as a non-volatilesource of data. The components 805 to 813 of the computer module 801,typically communicate via an interconnected bus 804 and in a mannerwhich results in a conventional mode of operation of the computer system800 known to those in the relevant art. Examples of computers on whichthe embodiments can be practised include IBM-PC's and compatibles, SunSparcstations or alike computer systems evolved therefrom.

Typically, the application program of the preferred embodiment isresident on the hard disk drive 810 and read and controlled in itsexecution by the processor 805. Intermediate storage of the program andany data fetched from the network 820 may be accomplished using thesemiconductor memory 806, possibly in concert with the hard disk drive810. In some instances, the application program may be supplied to theuser encoded on a CD-ROM or floppy disk and read via the correspondingdrive 812 or 811, or alternatively may be read by the user from thenetwork 820 via the modem device 816. Still further, the software canalso be loaded into the computer system 800 from other computer readablemedium including magnetic tape, a ROM or integrated circuit, amagneto-optical disk, a radio or infra-red transmission channel betweenthe computer module 801 and another device, a computer readable cardsuch as a PCMCIA card, and the Internet and Intranets including emailtransmissions and information recorded on websites and the like. Theforegoing is merely exemplary of relevant computer readable mediums.Other computer readable mediums may be practiced without departing fromthe scope and spirit of the invention.

The method of addressing an arbitrary fragment of an AV resource mayalternatively be implemented in dedicated hardware such as one or moreintegrated circuits performing the functions or sub functions ofaddressing. Such dedicated hardware may include graphic processors,digital signal processors, or one or more microprocessors and associatedmemories. The dedicated hardware described can be incorporated intospecialised or general purpose equipment which addresses AV content.

Adoption of XML as a notation for describing the preferred embodiment isa convenient mechanism for describing the embodiment. It also allows aconsistent view and addressing mechanism for both XML and non-XMLresources. As noted previously however, this is not an essential featureof the present invention.

INDUSTRIAL APPLICABILITY

It is apparent from the above that the embodiments of the invention areapplicable to the computer and data processing industries.

The foregoing describes only some embodiment of the present invention,and modifications and/or changes can be made thereto without departingfrom the scope and spirit of the invention, the embodiments beingillustrative and not restrictive.

1. A method for forming an address for locating an electronicallyaccessible Audio/Video (AV) fragment of AV content, said methodcomprising the steps of: determining a network address for locating theAV content, said AV content having a logical model which describes ahierarchical representation comprising two or more levels of detail forsaid AV content, wherein the logical model is based on at least one oftime blocks and spatial regions at a lowest level of the levels ofdetail, and wherein the logical model is adapted to address the fragmentof said AV content; generating a fragment identifier for at least onefragment corresponding to at least one of said levels of detail of saidAV content, using the logical model; and combining the network addressand the fragment identifier to form a URI reference, being an addressfor locating the AV fragment, thereby rendering the AV fragmentaddressable.
 2. The method according to claim 1, wherein generating thefragment identifier comprises providing an addressing scheme foraddressing said at least one fragment in terms of at least one of saidtime blocks and said spatial regions.
 3. The method according to claim2, wherein the addressing scheme for addressing said at least onefragment includes at least one of a time axis, a time function, a regionaxis, and a region function.
 4. The method according to claim 3, whereinthe AV content is a single file in a file system supporting Audio/Videocontent.
 5. The method according to claim 3, wherein the AV content isone from the group consisting of a Digital Versatile Disk (DVD), CompactDisk Read Only Memory (CD ROM), Audio Compact Disk (CD), Video Tape andAudio Tape.
 6. The method according to claim 3, wherein the addressingscheme provides a syntax for addressing one or more AV fragments in thefragment identifier.
 7. The method according to claim 2, wherein saidaddressing scheme is Xpath based.
 8. The method according to claim 1,wherein the fragment of AV content is not addressable by only thenetwork address.
 9. The method according to claim 1, wherein AV contentcomprises monolithic blocks of information represented by said two ormore levels of detail.
 10. The method according to claim 9, wherein saidfragment identifier uses a level of detail that is neither visible noraddressable.
 11. An apparatus for forming an address for locating anelectronically accessible Audio/Video (AV) fragment of AV content, saidapparatus comprising: a memory for storing a program; and a processorfor executing the program, said program comprising: code for determininga network address for locating the AV content, said AV content having alogical model which describes a hierarchical representation comprisingtwo or more levels of detail for said AV content, wherein the logicalmodel is based on at least one of time blocks and spatial regions at alowest level of the levels of detail, and wherein the logical model isadapted to address the fragment of said AV content; code for generatinga fragment identifier for at least one fragment corresponding to atleast one of said levels of detail of said AV content, using the logicalmodel; and code for combining the network address and the fragmentidentifier to form a URI reference, being an address for locating the AVfragment, thereby rendering the AV fragment addressable.
 12. Theapparatus according to claim 11, wherein the code for generating thefragment identifier comprises code for providing an addressing schemefor addressing said at least one fragment in terms of at least one ofsaid time blocks and said spatial regions.
 13. The apparatus accordingto claim 12, wherein the addressing scheme for addressing said at leastone fragment includes at least one of a time axis, a time function, aregion axis, and a region function.
 14. The apparatus according to claim13, wherein the AV content is a single file in a file system supportingAudio/Video content.
 15. The apparatus according to claim 13, whereinthe AV content is one from the group consisting of a Digital VersatileDisk (DVD), Compact Disk Read Only Memory (CD ROM), Audio Compact Disk(CD), Video Tape and Audio Tape.
 16. The apparatus according to claim13, wherein the addressing scheme provides a syntax for addressing oneor more AV fragments in the fragment identifier.
 17. The apparatusaccording to claim 12, wherein said addressing scheme is Xpath based.18. The apparatus according to claim 11, wherein AV content comprisesmonolithic blocks of information represented by said two or more levelsof detail.
 19. The apparatus according to claim 18, wherein saidfragment identifier uses a level of detail that is neither visible noraddressable.
 20. A computer program product including a computerreadable storage medium having recorded thereon a computer program fordirecting a processor to execute a method for forming an address forlocating an electronically accessible Audio/Video (AV) fragment of AVcontent, said program comprising: code for determining a network addressfor locating the AV content, said AV content having a logical modelwhich describes a hierarchical representation comprising two or morelevels of detail for said AV content, wherein the logical model is basedon at least one of time blocks and spatial regions at a lowest level ofthe levels of detail, and wherein the logical model is adapted toaddress the fragment of said AV content; code for generating a fragmentidentifier for at least one fragment corresponding to at least one ofsaid levels of detail of said AV content, using the logical model; andcode for combining the network address and the fragment identifier toform a URI reference, being an address for locating the AV fragment,thereby rendering the AV fragment addressable.
 21. The computer programproduct according to claim 20, wherein the code for generating thefragment identifier comprises code for providing an addressing schemefor addressing said at least one fragment in terms of at least one ofsaid time blocks and said spatial regions.
 22. The computer programproduct according to claim 21, wherein the addressing scheme foraddressing said at least one fragment includes at least one of a timeaxis, a time function, a region axis, and a region function.
 23. Thecomputer program product according to claim 22, wherein the AV contentis a single file in a file system supporting Audio/Video content. 24.The computer program product according to claim 22, wherein the AVcontent is one from the group consisting of a Digital Versatile Disk(DVD), Compact Disk Read Only Memory (CD ROM), Audio Compact Disk (CD),Video Tape and Audio Tape.
 25. The computer program product according toclaim 22, wherein the addressing scheme provides a syntax for addressingone or more AV fragments in the fragment identifier.
 26. The computerprogram product according to claim 21, wherein said addressing scheme isXpath based.
 27. The computer program product according to claim 20,wherein AV content comprises monolithic blocks of informationrepresented by said two or more levels of detail.
 28. The computerprogram product according to claim 27, wherein said fragment identifieruses a level of detail that is neither visible nor addressable.
 29. Amethod for forming an address for locating an electronically accessibleaudio fragment of audio content, said method comprising the steps of:determining a network address for locating the audio content, said audiocontent having a logical model which describes a hierarchicalrepresentation comprising two or more levels of detail for said audiocontent, wherein the logical model is based upon time blocks at a lowestlevel of the levels of detail, and wherein the logical model is adaptedto address the fragment of said audio content; generating a fragmentidentifier for at least one fragment corresponding to at least one ofsaid levels of detail of said audio content, using the logical model;and combining the network address and the fragment identifier to form aURI reference, being an address for locating the audio fragment, therebyrendering the audio fragment addressable.
 30. The method according toclaim 29, wherein audio content comprises monolithic blocks ofinformation represented by said two or more levels of detail.
 31. Themethod according to claim 30, wherein said fragment identifier uses alevel of detail that is neither visible nor addressable.
 32. A methodfor forming an address for locating an electronically accessible imagefragment of image content, said method comprising the steps of:determining a network address for locating the image content said imagecontent having a logical model which describes a hierarchicalrepresentation comprising two or more levels of detail for said imagecontent, wherein the logical model is based upon spatial regions at alowest level of the levels of detail, and wherein the logical model isadapted to address the fragment of said image content; generating afragment identifier for at least one fragment corresponding to at leastone of said levels of detail of said image content, using the logicalmodel; and combining the network address and the fragment identifier toform a URI reference, being an address for locating the image fragment,thereby rendering the image fragment addressable.
 33. The methodaccording to claim 32, wherein image content comprises monolithic blocksof information represented by said two or more levels of detail.
 34. Themethod according to claim 33, wherein said fragment identifier uses alevel of detail that is neither visible nor addressable.
 35. A methodfor forming an address for locating an electronically accessible videofragment of video content, said method comprising the steps of:determining a network address for locating the video content, said videocontent having a logical model which describes a hierarchicalrepresentation comprising two or more levels of detail for said videocontent, wherein the logical model is based upon at least one of timeblocks and spatial regions at a lowest level of the levels of detail,and wherein the logical model is adapted to address the fragment of saidvideo content; generating a fragment identifier for at least onefragment corresponding to at least one of said levels of detail of saidvideo content, using the logical model; and combining the networkaddress and the fragment identifier to form a URI reference, being anaddress for locating the video fragment, thereby rendering the videofragment addressable.
 36. The method according to claim 35, whereinvideo content comprises monolithic blocks of information represented bysaid two or more levels of detail.
 37. The method according to claim 36,wherein said fragment identifier uses a level of detail that is neithervisible nor addressable.